Application of computed tomography for the evaluation of obstetrically relevant measurements in German Holstein-Friesian calves

The aim of this study was to measure obstetrically relevant dimensions in calves manually and via computed tomography and to investigate their relationship with the dimensions of fetal body parts that are accessible to the obstetrician during early stages of vaginal delivery. Twenty Holstein-Friesian stillborn calves (Bos taurus) weighing 41.1 ± 3.7 kg (33.6-46.5 kg) were examined and the maximum height (H), width (W), circumference (C) and cross-sectional area (A) of their body was determined. The largest (P < 0.05) one-dimensional variable was the height of the thorax in the region of cranial sternum (H-Thorax; 29.3 ± 1.3 cm), and the largest (P < 0.05) two-dimensional variables were the cross-sectional area of the shoulder region at greater tubercles of the humeri (A-Shoulder; 307 ± 27 cm²) and of the thorax in the region of cranial sternum (A-Thorax; 306 ± 25 cm²). The dimensions of the front legs, which included the circumference of the canon bone and width of the fetlock joint, did not correlate (P > 0.05) with H-Thorax, A-Shoulder and A-Thorax. There were moderate significant correlations between the perpendicular height of the head (H-Head) and A-Thorax (r = 0.65, P < 0.05) and between the circumference of the head (C-Head) and A-Shoulder (r = 0.64, P < 0.05) and A-Thorax (r = 0.52, P < 0.05), but other relationships (P > 0.05) between the dimensions at the level of the head and H-Thorax, A-Shoulder and A-Thorax were not significant (P > 0.05). The results of this study show that the shoulders and thorax are the obstetrically most relevant calf dimensions, but the size of these variables cannot be reliably predicted by evaluating the dimensions of the forelimbs and head of calves during delivery.     

Helical differential X-ray phase-contrast computed tomography

We report on the first experimental results of helical differential phase-contrast computed tomography (helical DPC-CT) with a laboratory X-ray tube source and a Talbot–Lau grating interferometer. The results experimentally verify the feasibility of helical data acquisition and reconstruction in phase-contrast imaging, in analogy to its use in clinical CT systems. This allows fast and continuous volumetric scans for long objects with lengths exceeding the dimension of the detector. Since helical CT revolutionized the field of medical CT several years ago, we anticipate that this method will bring the same significant impact on the future medical and industrial applications of X-ray DPC-CT.     

Comparison of body composition in middle-aged and elderly males using computed tomography

Computed tomography (CT) scans were taken of 21 middle-aged men (mean age 46.3 years) and 20 older men (mean age 69.4 years) to measure differences in body composition with age. Overall, the older men weighed 8.2 kg less than the middle-aged men, and this difference was primarily the result of their having less lean tissue. Although fat mass (by whole body potassium counting) was only slightly less in older men, there were distributional differences in fat between the age groups. Total abdomen adipose tissue area (from CT) was similar in both groups, although the subcutaneous portion of the abdomen adipose tissue was less in the older men, and they had correspondingly more adipose tissue within the abdominal cavity. Muscle areas of the leg and arm were significantly less in the older men, as were all lean tissues of the abdomen and chest. When these data were corrected for differences in body weight with age, the results were still significant, suggesting a centripetalization and internalization of fat with age. Causes of this apparent fat redistribution and decrease of lean tissue with age were not revealed by this study and are presently unknown.     

Patient radiation biological risk in computed tomography angiography procedure

Computed tomography angiography (CTA) has become the most valuable imaging modality for the diagnosis of blood vessel diseases; however, patients are exposed to high radiation doses and the probability of cancer and other biological effects is increased. The objectives of this study were to measure the patient radiation dose during a CTA procedure and to estimate the radiation dose and biological effects.The study was conducted in two radiology departments equipped with 64-slice CT machines (Aquilion) calibrated according to international protocols. A total of 152 patients underwent brain, lower limb, chest, abdomen, and pelvis examinations. The effective radiation dose was estimated using ImPACT scan software. Cancer and biological risks were estimated using the International Commission on Radiological Protection (ICRP) conversion factors.The mean patient dose value per procedure (dose length product [DLP], mGy·cm) for all examinations was 437.8 ± 166, 568.8 ± 194, 516.0 ± 228, 581.8 ± 175, and 1082.9 ± 290 for the lower limbs, pelvis, abdomen, chest, and cerebral, respectively. The lens of the eye, uterus, and ovaries received high radiation doses compared to thyroid and testis. The overall patient risk per CTA procedure ranged between 15 and 36 cancer risks per 1 million procedures. Patient risk from CTA procedures is high during neck and abdomen procedures. Special concern should be provided to the lens of the eye and thyroid during brain CTA procedures. Patient dose reduction is an important consideration; thus, staff should optimize the radiation dose during CTA procedures.     

The naso-frontal joint in snakes as revealed by high-resolution X-ray computed tomography of intact and complete skulls

The naso-frontal joint of snakes is described on the basis of high-resolution X-ray computed tomography scans of single individuals of spirit-preserved snake specimens. The suspension of the snout unit from the braincase at the naso-frontal joint shows some broad evolutionary trends among snakes with potential phylogenetic implications, such as sutured or fused medial frontal flanges formed by the medial frontal pillars and the frontal subolfactory processes (in alethinophidians), the restriction of the usually extended dorsoventral contact of the medial nasal flange with the medial frontal flanges to a dorsal or ventral contact (in macrostomatans), and the transfer of the main element of snout suspension from the nasal to the septomaxilla (in colubroids). Some phylogenetic implications of the morphological characters identified in this study are outlined and discussed.     

Synthesis and characterization of ethosomal contrast agents containing iodine for computed tomography (CT) imaging applications

As a first step in the development of novel liver-specific contrast agents using ethosomes for computed tomography (CT) imaging applications, we entrapped iodine within ethosomes, which are phospholipid vesicular carriers containing relatively high alcohol concentrations, synthesized using several types of alcohol, such as methanol, ethanol, and propanol. The iodine containing ethosomes that were prepared using methanol showed the smallest vesicle size (392?nm) and the highest CT density (1107 HU). The incorporation of cholesterol into the ethosomal contrast agents improved the stability of the ethosomes but made the vesicle size large. The ethosomal contrast agents were taken up well by macrophage cells and showed no cellular toxicity. The results demonstrated that ethosomes containing iodine, as prepared in this study, have potential as contrast agents for applications in CT imaging.     

Alleged synapomorphy of the M1/I1 eruption pattern in robust australopithecines and Homo: evidence from high-resolution computed tomography

Ever since Broom and Robinson (1951) published their claim that the eruption pattern of permanent incisors in robust australopithecines was most similar to that of modern man and different from that of gracile australopithecines and apes, the accuracy of this observation has been the subject of periodic debate (e.g., Wallace: Ph.D. thesis, 1972; Dean: Am. J. Phys. Anthropol. 67:251-257, 1985; Grine: Am. J. Phys. Anthropol. 72:353-359, 1987). Part of the problem is that the developing incisors in one of the specimens most crucial to this argument (SK61) are difficult to visualize clearly by conventional radiographic techniques because of the heavy mineralization in the fossil. This study reanalyzes SK 61 by high-resolution computed tomography in order to contribute to the final resolution of its incisor development. Grine's (op. cit.) assessment of the incisors as the deciduous ones, not the permanent ones, is fully confirmed. This fact, in conjunction with the observation that permanent incisor root formation had only just commenced in this specimen, further weakens the argument of M1/I1 eruption pattern synapomorphy between Homo and robust australopithecines.     

Cranial anatomy of the Paleocene plesiadapiform Carpolestes simpsoni (Mammalia, Primates) using ultra high-resolution X-ray computed tomography, and the relationships of plesiadapiforms to Euprimates

Central to issues surrounding the origin of euprimates, affinities of Paleocene Carpolestidae have been controversial. Carpolestids have been classified as plesiadapoid primates, tarsiiform euprimates, dermopterans, or the sister taxon of euprimates to the exclusion of other plesiadapiforms, based exclusively on dental or postcranial data. Newly discovered crania of Carpolestes simpsoni from the latest Paleocene of the Clarks Fork Basin, Wyoming, are the first described for the family Carpolestidae. The two best preserved skulls were studied using ultra high-resolution X-ray computed tomography. Comparison of these specimens to those of other stem primates (Plesiadapiformes) demonstrates that the diversity of cranial morphology in this group is greater than previously thought. Carpolestes differs from euprimates and is similar to other plesiadapiforms (Ignacius and Plesiadapis) in lacking a postorbital bar and having a relatively long rostrum. Carpolestes is similar to fossil euprimates and Plesiadapis in having a bullar morphology consistent with a petrosal origin, and differs from Ignacius, in which the bulla is composed of the entotympanic. Carpolestes differs from primitive euprimates and all other known plesiadapiforms in possessing a two-chambered auditory bulla, similar to that of modern Tarsius. However, Carpolestes had an internal carotid artery (ICA) that took a transpromontorial route from a posteromedially positioned posterior carotid foramen (pcf), unlike Tarsius, in which this artery takes a perbullar route from an anterolaterally positioned pcf. Carpolestes has clear grooves on the promontorium for both the promontorial and stapedial arteries, indicating that it had an unreduced internal carotid circulation, similar to that of early euprimates. Carpolestes differs from primitive euprimates and some specimens of Ignacius in not having bony tubes surrounding the branches of the ICA. Cladistic analysis of cranial data fails to support a close relationship of Carpolestidae to either tarsiiform euprimates or extant Dermoptera, but suggests a close relationship between Carpolestidae, Plesiadapidae, and Euprimates.     

Adaptive bolus-chasing computed tomography angiography in the cases of symmetric and asymmetric arterial flows in peripheral arteries

Synchronization of the contrast bolus peak and CT imaging aperture is a crucial issue for computed tomography angiography (CTA). It affects the CTA image quality and the amount of contrast dose. A whole-body CTA procedure means to scan from the abdominal aorta to pedal arteries. In this context, the synchronization is much more difficult with the asymmetric arterial flow in lower extremities than in the case of symmetric arterial flow. In this paper, we propose an adaptive optimal controller to chase the contrast bolus peak while it propagates in the aorta and lower extremities with symmetric flow. In the case of asymmetric flow after the contrast bolus splitting into two lower limbs, we propose a dynamic programming approach to cover the lower limbs optimally. Simulation and experimental results show that the proposed methods outperform the current constant-speed method substantially.     

A quantitative method for the evaluation of three-dimensional structure of temporal bone pneumatization

Temporal bone pneumatization has been included in lists of characters used in phylogenetic analyses of human evolution. While studies suggest that the extent of pneumatization has decreased over the course of human evolution, little is known about the processes underlying these changes or their significance. In short, reasons for the observed reduction and the potential reorganization within pneumatized spaces are unknown. Technological limitations have limited previous analyses of pneumatization in extant and fossil species to qualitative observations of the extent of temporal bone pneumatization. In this paper, we introduce a novel application of quantitative methods developed for the study of trabecular bone to the analysis of pneumatized spaces of the temporal bone. This method utilizes high-resolution X-ray computed tomography (HRXCT) images and quantitative software to estimate three-dimensional parameters (bone volume fractions, anisotropy, and trabecular thickness) of bone structure within defined units of pneumatized spaces. We apply this approach in an analysis of temporal bones of diverse but related primate species, Gorilla gorilla, Pan troglodytes, Homo sapiens, and Papio hamadryas anubis, to illustrate the potential of these methods. In demonstrating the utility of these methods, we show that there are interspecific differences in the bone structure of pneumatized spaces, perhaps reflecting changes in the localized growth dynamics, location of muscle attachments, encephalization, or basicranial flexion.     

Aspects of positron emission tomography radiochemistry as relevant for food chemistry

Summary. Positron emission tomography (PET) is a medical imaging technique using compounds labelled with short-lived positron emitting radioisotopes to obtain functional information of physiological, biochemical and pharmacological processes in vivo. The need to understand the potential link between the ingestion of individual dietary agents and the effect of health promotion or health risk requires the exact metabolic characterization of food ingredients in vivo. This exciting but rather new research field of PET would provide new insights and perspectives on food chemistry by assessing quantitative information on pharmocokinetics and pharmacodynamics of food ingredients and dietary agents. To fully exploit PET technology in food chemistry appropriately radiolabelled compounds as relevant for food sciences are needed. The most widely used short-lived positron emitters are ¹¹C (t_1/2 = 20.4 min) and ¹⁸F (t_1/2 = 109.8 min). Longer-lived radioisotopes are available by using ⁷⁶Br (t_1/2 = 16.2 h) and ¹²⁴I (t_1/2 = 4.12 d). The present review article tries to discuss some aspects for the radiolabelling of food ingredients and dietary agents either by means of isotopic labelling with ¹¹C or via prosthetic group labelling approaches using the positron emitting halogens ¹⁸F, ⁷⁶Br and ¹²⁴I.     

New discoveries on the middle ear anatomy of Ignacius graybullianus (Paromomyidae,Primates) from ultra high resolution X-ray computed tomography

A skull of Ignacius graybullianus (USNM 421608) was studied using ultra high resolution X-ray computed tomography (uhrCT). The anatomy of the middle ear in this specimen was previously studied through partial removal of the auditory bulla on one side. The data now available allow for examination of the others unprepared ear, which is more completely preserved, as well as adding to the information available about the previously studied ear. Analysis of the relationships between the bones making up the auditory bulla confirms previous assertions that it is formed from the entotympanic, and not from the petrosal, basioccipital, or basisphenoid. Contrary to previous reconstructions of the middle ear anatomy in all known plesiadapiforms, this specimen exhibits a bony canal for the promontorial artery and/or internal carotid nerves running across the lateral extreme of the promontorium. The identification of this structure is confirmed by the clear presence of a lumen, and its origination at a posterior carotid foramen (pcf) in a position that corresponds to that identified in previous studies of the paromomyid basicranium (Am. J. Phys. Anthropol., 36 (1972) 59, Am. J. Phys. Anthropol., 89 (1992) 477). Remnants of this canal are present bilaterally in USNM 421608, which additionally supports its identification. The presence of bony canals for branches of the internal carotid artery and the internal carotid nerves is a feature seen in scandentians and euprimates that is missing in dermopterans. The unusual lateral route followed by the internal carotid nerves is a primitive euprimate feature missing in all other archontans. As such, this evidence is consistent with a close euprimate-paromomyid relationship, and the inclusion of the latter in the order Primates. The discovery of this feature in paromomyids after almost 30 years of study of the ear region of this family acts as a cautionary note to the interpretation of the middle ear in damaged specimens.     

Sexual dimorphism in the pelvic midplane and its relationship to Neandertal reproductive patterns

The fragmentary nature of the fossil record has limited the analysis of the Neandertal pelvis to the superior pubic ramus and the pelvic inlet. From an obstetric viewpoint, the pelvic midplane or “plane of least dimensions,” defined by the distance between the ischial spines, must be considered in the analysis of hominid reproduction. We examined the relationship between BSD and weight in a mixed sex hospital population undergoing diagnostic computed tomography (CT) scans (41 females and 40 males). Because femoral head diameter squared (FH²) has been used as a proxy for weight in skeletal populations, it was also analyzed with respect to BSD and weight. Bivariate regression analysis of BSD with other body dimensions indicates the presence of significant sex differences. In females, but not in males, weight is a statistically significant predictor of BSD. FH² is an even better predictor of BSD in females while nonsignificant in males. Although weight and FH² are significantly correlated with BSD in females, FH² does not predict weight in females as well as it does in males. The positive correlation between skeletal frame size and BSD in females is indicative of an evolutionary pattern that must take into account the pressures of reproduction. Our results indicate that critical dimensions of the pelvis must increase as the maternal skeleton becomes larger. These results provide a context for the interpretation of the reproductive patterns of a relatively robust hominid population like the Neandertals. © 1996 Wiley-Liss, Inc.     

Computed tomography and automated image analysis of prehistoric femora

Non-invasive characterization of limb bone cross-sectional geometry would be useful for biomechanical analyses of skeletal collections. Computed tomography (CT) is potentially the method of choice. Additionally, CT images are suitable for automated analysis. CT is here shown to be both accurate and precise in the analysis of cross-sectional geometry of prehistoric femora. Beam hardening artifacts can be reduced by using a water bath. As the availability of CT for research increases, both bone density and geometry could be determined simultaneously with this method.     

Visualizing the macroscale spatial distributions of biofilms in complex flow channels using industrial computed tomography

Abstract

The presence of biofilms in enclosed pipelines can lead to numerous deleterious issues. To date, it has been difficult to use optical imaging techniques to monitor the macroscale spatial distributions of biofilms. To address this concern, a combination of industrial computed tomography (ICT) and a contrast agent was explored to noninvasively visualize biofilms in three types of drip irrigation emitters. The results showed that ICT successfully observed and quantified the macroscale spatial distributions of biofilms. The complex hydrodynamic characteristics in the emitter channels affected the local distributions of biofilms. Biofilms were mainly attached to the lateral and medial faces and biomass decreased along the flow directions. Based on the distributions of biofilms, some emitter structural design defects were further diagnosed. Applying ICT in combination with the contrast agent could potentially provide a visual and effective way to reveal the formation mechanisms of biofilms and to optimize flow channel structures to avoid biofilm accumulations.     

Proliferation and apoptosis in subcutaneous adipose tissue of lactating cows with different genetic merit for milk yield

The aim of this study was to investigate the adipocyte size and fate in subcutaneous fat (scAT) of cows diverging for genetic merit at mid lactation stage, when anabolic activity increases and animals are in a state of positive energy balance. Twenty mid lactation cows (180 ± 20 days in milk) grouped according to the Estimated Breeding Values (EBV) for milk yield in plus (EBVp) and minus (EBVm) variants were selected. Average of adipocytes area, proliferation and apoptotic labelling index as well as DLK-1 expression, a marker of pre-adipocytes, were immunohistochemically evaluated in scAT biopsies. In EBVp cows, the BCS was lower (P < 0.01) whereas milk yield, protein, fat yield (P < 0.001) and plasma free fatty acid concentration (P < 0.05) were higher. The scAT of EBVp cows showed a significantly (P < 0.001) higher frequency between 500 and 3000 μm² classes in comparison to EBVm cows, that showed a significantly (P < 0.01) higher apoptotic labeling index. The immunohistochemical reaction showed DLK-1 positivity in scAT of EBVp cows. Taking together, the data indicate a link between milk yield genetic merit of cows, scAT morphology and function, suggesting greater dynamics and metabolic flexibility in EBVp cows.     

Retrograde perfusion and filling of mouse coronary vasculature as preparation for micro computed tomography imaging

Visualization of the vasculature is becoming increasingly important for understanding many different disease states. While several techniques exist for imaging vasculature, few are able to visualize the vascular network as a whole while extending to a resolution that includes the smaller vessels. Additionally, many vascular casting techniques destroy the surrounding tissue, preventing further analysis of the sample. One method which circumvents these issues is micro-Computed Tomography (μCT). μCT imaging can scan at resolutions <10 microns, is capable of producing 3D reconstructions of the vascular network, and leaves the tissue intact for subsequent analysis (e.g., histology and morphometry). However, imaging vessels by ex vivo μCT methods requires that the vessels be filled with a radiopaque compound. As such, the accurate representation of vasculature produced by μCT imaging is contingent upon reliable and complete filling of the vessels. In this protocol, we describe a technique for filling mouse coronary vessels in preparation for μCT imaging. Two predominate techniques exist for filling the coronary vasculature: in vivo via cannulation and retrograde perfusion of the aorta (or a branch off the aortic arch), or ex vivo via a Langendorff perfusion system. Here we describe an in vivo aortic cannulation method which has been specifically designed to ensure filling of all vessels. We use a low viscosity radiopaque compound called Microfil which can perfuse through the smallest vessels to fill all the capillaries, as well as both the arterial and venous sides of the vascular network. Vessels are perfused with buffer using a pressurized perfusion system, and then filled with Microfil. To ensure that Microfil fills the small higher resistance vessels, we ligate the large branches emanating from the aorta, which diverts the Microfil into the coronaries. Once filling is complete, to prevent the elastic nature of cardiac tissue from squeezing Microfil out of some vessels, we ligate accessible major vascular exit points immediately after filling. Therefore, our technique is optimized for complete filling and maximum retention of the filling agent, enabling visualization of the complete coronary vascular network--arteries, capillaries, and veins alike.